Nigerian authorities insisted on Wednesday that that there was no evidence that the Daesh (ISIS) militant group had established a base in the West African country.

"We wish to state that there is no evidence that the Islamic State [the name by which Daesh is known] operates in Nigeria," Mike Omeri, head of the National Information Center on Counter-terrorism, told reporters at a news briefing in Abuja.

"The latest attempt by Boko Haram to identify with the group is an act of desperation aimed at seeking attention and possible assistance from outside in the face of the crushing defeat they are suffering at the hands of the Nigerian armed forces and other regional collaborators," he declared.

Nigeria continues to fight a six-year insurgency that has claimed tens of thousands of lives and displaced over one million people from the northeastern region, where the militancy has been most ruthless.

Last year, Boko Haram went from attacking communities and planting bombs to capturing entire towns.

In mid-2014, it declared a self-styled "Islamic caliphate" in areas under its control with its headquarters in Gwoza, a hilly town in Nigeria's northeastern Borno State.

But Nigerian troops – joined by troops from Niger, Chad and Cameroon – have recently rolled back the gains made by the militants, liberating several Boko Haram-held towns and launching frontal attacks on the group's hideouts.

Omeri said the military and its regional partners were flushing the militants from their strongholds.

"The government wishes to assure Nigerians that this tempo will be sustained until every presence of the Boko Haram insurgency is totally obliterated in Nigeria," he asserted.

The official added: "The only nation that will exist in Nigeria is the united federal Republic of Nigeria, which demands the cooperation, commitment and patriotism of all its citizens."